The incidence of End Stage Renal Disease, with its attendant morbidity, mortality and health care costs continues to rise every year. In addition, the risk of cardiovascular disease (CVD) is approximately 30 times higher in patients with chronic renal insufficiency (CRI) compared to the general population. This project proposes to follow a cohort of 3000 patients with CRI to determine the factors associated with decline in renal function and the development and progression of CVD. This will set the stage to develop strategies to reduce the progression of CRI and CVD in this high-risk population. This center has assembled a multidisciplinary team of experienced investigators with documented expertise in recruitment and retention of participants in long term cardiovascular and renal trials. Another strength of our center is the collaborative approach between the diverse health care systems encompassing the vast majority of the health care market in this area (Cleveland Clinic Foundation, Louis Stokes Cleveland VAMC, Metrohealth Medical Center, Ohio Permanente Medical Group, and University Hospitals of Cleveland). It has already been determined that over 14,000 patients in these institutions have a documented serum creatinine level that would make them eligible for participation in this study. Patient identificationand recruitment will be consistent with current guidelines regarding confidentiality. Baseline evaluation will include assessment of renal function, and prevalent clinical and subclinical CVD. Relevant patient, environmental, and access to health care related factors that may contribute to progression of renal insufficiency will be measured. Traditional cardiovascular risk factors, as well as those associated with the underlying disease and renal dysfunction will also be assessed. Serial measurements of central arterial compliance will be performed in a subset of patients. Patients will be followed with annual examinations and phone interviews every six months. Clinically relevant outcomes of renal and cardiovascular disease are proposed. Our experienced research staff will be instrumental in the retention of participants and ascertainment of outcomes.